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1. 将Geom_BSplineSurface转化成TopoDS_Face:
Handle_Geom_BSplineSurface BSurface;
BRep_Builder builder;TopoDS_Face Face;builder.MakeFace(Face,BSurface,Tolerance);
Handle_Geom_Surface currentSur;TopExp_Explorer Ex; Ex.Init(shape,TopAbs_FACE); TopoDS_Face currentVt = TopoDS::Face(Ex.Current());currentSur = BRep_Tool::Surface(currentVt);
Handle(Geom_Curve) ResCurve ; Handle(Geom_TrimmedCurve) myTrimmed = new Geom_TrimmedCurve(ResCurve, 0, 1); NurbsCurve = GeomConvert::CurveToBSplineCurve(myTrimmed); //必须指定曲线的类型如Geom_TrimmedCurve
OCC的说明如下:
-- Purpose : This function converts a non infinite curve from
-- Geom into a B-spline curve.C must be an ellipse or a
-- circle or a trimmed conic or a trimmed line or a Bezier
-- curve or a trimmed Bezier curve or a BSpline curve or a
-- trimmed BSpline curve or an OffsetCurve. The returned B-spline is
-- not periodic except if C is a Circle or an Ellipse.
GeomConvert::SurfaceToBSplineSurface(surface)
其中surface必须为Geom_Surface 中的某一具体类型
OCC的说明如下:
--- Purpose : This algorithm converts a non infinite surface from Geom
-- into a B-spline surface.
-- S must be a trimmed plane or a trimmed cylinder or a trimmed cone
-- or a trimmed sphere or a trimmed torus or a sphere or a torus or
-- a Bezier surface of a trimmed Bezier surface or a trimmed swept
--surface with a corresponding basis curve which can be turned into
-- a B-spline curve
Handle_Geom_BSplineSurface CMiniCADTool::BuildSurface(const TColgp_SequenceOfXYZ& seqOfXYZ){ // Build the surface: // points are projected on plane z = 0 // the projection vector for each point is computed // These data give the input constraints loaded into plate algorithm const Standard_Integer nbPnt = seqOfXYZ.Length(); Standard_Integer i; //Filling plate Plate_Plate myPlate; for (i=1; i<= nbPnt; i += 4) { gp_Vec aVec(0., 0., seqOfXYZ.Value(i).Z()); gp_XY pntXY(seqOfXYZ.Value(i).X(),seqOfXYZ.Value(i).Y()); Plate_PinpointConstraint PCst( pntXY,aVec.XYZ() ); myPlate.Load(PCst); // Load a pinpoint constraint } myPlate.SolveTI(2, 1.); // Solving plate equations if (!myPlate.IsDone()) { return Handle(Geom_BSplineSurface)(); } // Computation of plate surface gp_Pnt Or(0,0,0.); gp_Dir Norm(0., 0., 1.); Handle(Geom_Plane) myPlane = new Geom_Plane(Or, Norm);// Plane of normal Oz Handle(GeomPlate_Surface) myPlateSurf = new GeomPlate_Surface(myPlane, myPlate);//plate surface GeomPlate_MakeApprox aMKS(myPlateSurf, Precision::Approximation(), 4, 7, 0.001, 0);//bspline surface return aMKS.Surface();}
to be continue......
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